The National Wildlife Health Center, an arm of the U.S. Geological Survey that assesses the impact of disease on wildlife, on Friday issued a wildlife bulletin on the deaths of common murres over the last 11 months.

Murre carcasses from the dozens to thousands have been found on beaches from the Alaska Panhandle to the east Aleutian Islands.

The bulletin notes large floating aggregations of lethargic murres in Prince William Sound that are “exhibiting minimal avoidance behavior.”

Testing of carcasses has found most dead birds to be emaciated.

The bulletin says more research is needed to determine whether unprecedented warm ocean temperatures may be affecting seabird prey.